The War File: Tanks!: Sturmartillerie (1998) DVD
 
The fast-moving Panzer Grenadier formations of the Blitzkrieg needed a mobile, well-armoured artillery presence to support their lightning thrusts into Poland, France and Russia. They found it in the form of the Sturmartillerie. This is the story of the developments which led to the Wespe, Hummel and the super heavy mortars of the Karl series. This episode contains: Extensive use of rare footage from Russian, German and Allied sources. Superb 3D graphics to illustrate the design and development of the Sturmartillerie. The views of the world's leading tank experts and historians, including David Fletcher, Professor John Erickson and Dr William Atwater. New footage of surviving Panzers. Features the self-propelled guns Wirbelwind, the Karl Super Mortar, Wespe, Hummel, Goliath, and more.